JP4419490B2 - Control device for automatic transmission - Google Patents

Description

  The present invention relates to a control device for an automatic transmission, and more particularly to a control device for an automatic transmission that can reduce a decrease in durability of a one-way clutch of the automatic transmission.

  In an automatic transmission used in a vehicle such as an automobile, a plurality of clutches and brakes are engaged and released. If these operations are out of synchronization, a large shock is generated when the gear is shifted, so synchronization can be performed automatically. As described above, a one-way clutch is often used in combination with a brake or a clutch.

  By the function of the one-way clutch, smooth shifting can be performed without using a special mechanism or complicated control. A one-way clutch is a device that transmits rotation only to one side and idles to the other. When a one-way clutch is installed, for example, the engine power is received and transmitted at low speeds, but when the power is transmitted from another gear at the upper gear, it has been idle until then. Smooth transmission can be performed by stopping transmission of power.

  Japanese Patent Application Laid-Open No. 5-126217 discloses a configuration of an automatic transmission in which a one-way clutch is incorporated.

Japanese Patent Laid-Open No. 5-126217

  By the way, for example, when the vehicle travels on a so-called rough road with many irregularities, when descending from a step, or when moving from a low μ road to a high μ road, tire slipping and slipping occurred. The tire will grip later. When the tire is gripped after idling or slipping, a large torque is applied to the drive system including the transmission from the road surface side (drive wheel side).

  As a result of earnest research by the present inventors, the following findings were obtained for the first time. That is, when a large torque as described above is applied, if the gear stage at that time is configured only by a friction engagement device (brake or clutch), the friction engagement device has robustness against slippage. Therefore, when the one-way clutch is involved in the gear position at that time and a large torque is applied to the one-way clutch, the one-way clutch is durable. It has been found that there is a possibility of adversely affecting

  An object of the present invention is to provide a control device for an automatic transmission that can reduce the risk of a decrease in durability of a one-way clutch of the automatic transmission.

The control device for an automatic transmission according to the present invention is a control device for an automatic transmission that is configured by operating a one-way clutch in a part of a plurality of shift speeds that can be formed. An estimation means for estimating that a load of a predetermined value or more is input to the machine, and a part of the plurality of shift stages is configured by operating a one-way clutch. When a load greater than a predetermined value is input to the machine, the one-way clutch is registered as a one-way clutch operating stage as a shift stage that may be loaded with a load greater than a set value. The other part of the shift speeds is configured by shifting the one-way clutch without operating the one-way clutch, or by operating the one-way clutch. When the load is input, the one-way clutch is registered as being a one-way clutch inoperative stage because it is not likely to be loaded beyond the set value, and from the road surface to the automatic transmission On the other hand, when it is estimated that a load of a predetermined value or more is input, if the shift stage of the automatic transmission is the one-way clutch operation stage, the shift stage of the automatic transmission is changed to the one-way clutch non-operation stage. And a control unit for controlling so as to be.
In addition, when it is estimated that a load greater than a predetermined value is not input to the automatic transmission from the road surface, the control unit travels at the one-way clutch operating stage if the automatic transmission is in the one-way clutch operating stage. It is characterized by doing.

  According to the control apparatus for an automatic transmission of the present invention, when a load greater than a predetermined value is input from the road surface to the automatic transmission, which is estimated by the estimation means, the shift speed is controlled to the one-way clutch inoperative stage. Therefore, the durability of the one-way clutch is not adversely affected by inputting a load of a predetermined value or more from the road surface to the automatic transmission.

  In the control apparatus for an automatic transmission according to the present invention, the estimation means determines tire slip and estimates that a load of a predetermined value or more is input based on the determination result. As a case where a large load is input from the road surface to the automatic transmission, there is a case where the tire grips on the road surface after slipping. When gripping after a tire slip, the load input from the road surface to the automatic transmission is large.

  In the control apparatus for an automatic transmission according to the present invention, the estimation means determines a road surface condition and estimates that a load of a predetermined value or more is input based on the determination result. Here, the road surface state includes, for example, unevenness and steps on the road surface.

  In the control device for an automatic transmission according to the present invention, the estimation means is greater than or equal to a predetermined value based on information indicating a road surface state stored in advance in the vehicle or information indicating a road surface state input through communication with the outside of the vehicle. It is characterized in that it is estimated that a certain load is input. Here, the information indicating the road surface condition stored in advance in the vehicle is accumulated based on information recorded on a recording medium (HD or DVD) as a part of the car navigation system or past actual driving of the vehicle itself. Contains information. Further, the road surface state input through communication with the outside of the vehicle includes information obtained by communication with other vehicles, the center, the communication device on the road side, and the broadcasting station.

  According to the control device for an automatic transmission of the present invention, the risk of a decrease in durability of the one-way clutch is reduced.

  Hereinafter, an embodiment of a control device for an automatic transmission according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
In the present embodiment, torque / load (hereinafter referred to as “road surface input”) input from the road surface to the vehicle side is predicted (estimated), and as a result, a large road surface input (hereinafter simply referred to as “large road surface input”) of a predetermined value or more. )) Is predicted, the automatic transmission shifts from the one-way clutch operation stage (hereinafter referred to as OWC operation stage) to the one-way clutch non-operation stage (hereinafter referred to as OWC non-operation stage). And / or shifting to the OWC operating stage is prohibited.

In the above, “road surface input” is torque including inertia torque more than the torque generated by the engine, and is also referred to as tire input or rear input. The “OWC operation stage” is configured by the operation (engagement) of the one-way clutch, and when a large road surface input is input to the vehicle, the one-way clutch is applied with a large torque that is greater than the set value. This means the gear position set as possible. In addition, the “OWC non-operational stage” is a gear stage configured without the one-way clutch operating, and a one-way clutch operating, and when a large road surface input is input to the vehicle side, The one-way clutch is a shift stage that is set such that there is no possibility that a large torque exceeding the set value is applied.

  First, an automatic transmission used in the present embodiment will be described with reference to FIG. The automatic transmission 10 is known per se, and bypasses the input shaft 2 connected to the output shaft of an engine (not shown), a fluid type torque converter 3, and the torque converter 3. The direct coupling clutch 4 that directly couples the input shaft 2 to the output shaft 3a of the torque converter 3 and the shaft 5 that is connected to the output shaft 3a of the torque converter 3 serve as the input shaft, and several shift speeds are applied to the input shaft 5. A gear transmission mechanism 7 is provided that outputs a driving force for driving a driving wheel (not shown) of the vehicle to the output shaft 6.

  The automatic transmission 10 is a five-speed automatic transmission, and includes a main transmission 8 that achieves four forward speeds and one reverse speed, and a front overdrive transmission 9. The main transmission 8 includes three sets of planetary gears 15, 16, 17 and clutches C 1, C 2, F 1, F 2 for engaging and releasing these transmission elements (sun gear, planetary carrier, ring gear) and a brake for fixing / releasing the gears. B1 to B4. The front overdrive transmission 9 engages, releases, and fixes the speed change elements (sun gear, planetary carrier, ring gear) of the overdrive (hereinafter referred to as O / D) planetary gear 12 connected to the input shaft 113 to establish a direct connection stage. And achieving an overdrive stage.

  In FIG. 7, C0 is an O / D clutch, which connects the planetary carrier 12c of the O / D planetary 12 and the sun gear 12s. C1 is a forward clutch that connects the input shaft 113 and the intermediate shaft 114. C2 is a direct clutch that connects the input shaft 113 and the sun gear 15s in which the front planetary 15 and the center planetary 16 are integrated.

  B0 is an O / D brake that locks the rotation of the sun gear 12s of the O / D planetary 12. B1 is a 3rd coast brake and locks the rotation of the sun gear 15s of the front planetary 15 and the center planetary 16. B2 is a 3rd brake that locks the outer race of the first one-way clutch F1. B3 is a 2nd brake and locks the rotation of the planetary carrier 15c of the front planetary 15. B4 is a 1st & Rev brake, and locks the rotation of the ring gear 17r of the rear planetary 17.

  F0 is an O / D one-way clutch that locks the left rotation of the planetary carrier 12c relative to the sun gear 12s of the O / D planetary 12. F1 is a first one-way clutch that locks the left rotation of the sun gear 15s of the front planetary 15 and the center planetary 16 when the 3rd brake B2 is operated. F2 is a second one-way clutch, and locks the left rotation of the ring gear 17r of the rear planetary 17.

  FIG. 8 is an operation table of the automatic transmission 10 and shows engagement states of the clutches C0 to C2, the brakes B0 to B4, and the one-way clutches F0 to F2 that are achieved under the respective shift ranges. In FIG. 8, .largecircle. Indicates engagement, and .DELTA. Indicates engagement but no power transmission. The shift positions P, R, N, D, 4, 3, 2 and L indicate parking, reverse, neutral, D range, 4 range, 3 range, 2 range and L range, respectively. In addition, 1st, 2nd, 3rd, 4th, and 5th indicate the first speed, second speed, third speed, fourth speed, and fifth speed, respectively.

  With reference to FIG. 8, the operation (engagement) state of the O / D one-way clutch and the first and second one-way clutches F0, F1, and F2 at each gear position will be described. In the first speed, the O / D one-way clutch F0 and the second one-way clutch F2 are operated, and the first one-way clutch F1 is not operated. At the second speed, the O / D one-way clutch F0 is operated, and the first and second one-way clutches F1 and F2 are not operated. In the third speed, the O / D one-way clutch F0 and the first one-way clutch F1 are operated, and the second one-way clutch F2 is not operated. At the fourth speed, the O / D one-way clutch F0 is operated, and the first and second one-way clutches F1 and F2 are not operated. In the fifth speed, the O / D one-way clutch and the first and second one-way clutches F0, F1, and F2 are not operated.

  When a large torque is input from the road surface to the vehicle side, the O / D one-way clutch F0 receives the input torque so as to be shared with the O / D clutch C0. It is considered that the above large torque is not applied. Therefore, the second speed and the fourth speed configured by operating only the O / D one-way clutch F0 of the one-way clutch are mapped (registered) in advance as being in the OWC non-operating stage. Further, the fifth speed is mapped in advance as an OWC non-operational stage because it is a shift stage configured without the one-way clutch operating.

  On the other hand, when a large torque is input from the road surface to the vehicle side, it is considered that the first one-way clutch F1 and the second one-way clutch F2 may each be applied with a large torque that is greater than a set value. Therefore, the first speed configured by operating the second one-way clutch F2 and the third speed configured by operating the first one-way clutch F1 are mapped in advance as being in the OWC operating stage. .

  In the automatic transmission 10 shown in FIGS. 7 and 8, the second speed and the fourth speed configured by operating only the O / D one-way clutch F0 of the one-way clutch are OWC non-operating stages. However, instead of the configuration, in other automatic transmissions (not shown), all the shift stages configured by operating one-way clutch are registered as OWC operating stages. Only the gear stage configured without operating one one-way clutch can be registered as the OWC non-operation stage.

  Next, the control method of this embodiment will be described with reference to FIG.

  First, in step S1, the flag F is checked. The flag F indicates whether or not a shift command to the OWC non-operation stage and a shift prohibition instruction (step S4) to the OWC operation stage are issued as a result of predicting (estimating) a large road surface input. If a shift command to the OWC non-operation stage and a shift prohibition instruction to the OWC operation stage have been issued, F = 1, and if not, F = 0. Since F = 0 at the beginning of the flow, the process proceeds to step S2. If F = 1, the process proceeds to step S5.

  In step S2, it is determined whether or not a large road surface input is expected (estimated). For example, when driving on rough roads with many bumps, when descending from a level difference, or when moving from a low μ road to a high μ road, the tire grips after slipping or slipping of the tire. When the tire slips (engine blows up) or grips after slipping, a large torque is applied to the drive system including the transmission from the road surface side (drive wheel side). In step S2, it is determined whether or not such a large road surface input is predicted. The prediction method will be described later.

Further, in step S2, not only when a large road surface input is predicted based on the road surface condition that is currently traveling, but also on a large road surface based on information about the road surface scheduled to travel in the future (such as navigation information). This includes cases where input is predicted. Here, the navigation information includes road surface information (for example, non-paved road) recorded in advance in a storage medium (DVD, HD, etc.) as in the car navigation system, as well as past actual driving and other information. Information obtained through communication with vehicles and communication centers (including vehicle-to-vehicle communication and road-to-vehicle communication) is included. The communication includes a road traffic information communication system (VICS) and so-called telematics (G-BOOK (trademark), etc.).

  When a large road surface input is predicted as a result of step S2, the process proceeds to step S3. On the other hand, when a large road surface input is not predicted as a result of step S2 (step S2-N), no special control is performed and reset is performed.

  In step S3, it is determined whether or not the gear position at the time when a large road surface input is predicted to be input to the vehicle in step S2 is the OWC operation stage. That is, when a large road surface input is predicted immediately from the current time point in step S2, it is determined whether or not the gear position at the current time point is the OWC operation stage. Further, when a large road surface input is predicted after a while from the current time point in step S2, the gear position at the time point when the large road surface input is predicted, not the current time point, is the OWC operation stage. It is determined whether or not there is.

  For example, the current gear stage is an OWC non-operating stage, but at the point (location) at which a large road surface input is predicted, it is predicted that the vehicle is accelerated (or decelerated) from the current point in time, so an upshift ( If it is predicted that the OWC operation stage has been established by downshifting), it is determined in step S3 that it is “the OWC operation stage when a large road surface input is predicted”, and the process proceeds to step S4.

  Also, when the driving wheel is temporarily separated from the road surface when overcoming the step, and as a result, the engine speed is increased, and it is predicted that the engine will be upshifted to the OWC operating stage, affirmative in step S3. Will be judged. This is because the durability of the one-way clutch is adversely affected if the OWC operating stage is when the driving wheel comes in contact with the road surface when descending from the step (when a large road surface input is input).

  If a positive determination is made in step S3, the process proceeds to step S4. On the other hand, as a result of step S3, when it is not determined that the gear position at the time when a large road surface input is predicted to be input to the vehicle side is the OWC operation stage (step S3-N), special control is performed. It is not reset.

  In step S4, a command for shifting to the OWC non-operating stage is issued, and shifting to the OWC operating stage is prohibited. As described above, when the shift stage of the automatic transmission 10 is set to the OWC non-operation stage, even if a large road surface input is input to the vehicle side, the durability of the one-way clutch of the automatic transmission 10 is adversely affected. No. In the non-operating stage of OWC consisting only of friction engagement devices (brake and clutch), the friction engagement device is robust against slipping, so there is a problem with durability even if it slides in response to a large road surface input. Does not occur. In addition, when the one-way clutch is operated, and when a large road surface input is input from the road surface to the vehicle side, it is set that there is no possibility that the one-way clutch is subjected to a large torque exceeding the set value. In the operating stage, even if a large road surface input is input to the vehicle side, the durability of the one-way clutch is not adversely affected.

In step S4, immediately after the positive determination is made in step S3, a shift command to the OWC non-operation stage and a shift prohibition instruction to the OWC operation stage can be output. Alternatively, instead of this configuration, in step S4, after a positive determination is made in step S3, the gear position at the time when a large road surface input is predicted to be input to the vehicle side in step S2 becomes the OWC operation stage. The shift command to the OWC non-operation stage and the shift prohibition instruction to the OWC operation stage can be output only within the range of the purpose of preventing this. For example, the shift command to the OWC non-operation stage and the shift prohibition instruction to the OWC operation stage can be output only at the time when the road surface input is predicted to be input.

  The OWC non-operating stage to be shifted in step S4 is preferably close to the current shift stage in order to prevent the driver from feeling uncomfortable at the time of transition or return. After step S4, the process proceeds to step S5.

  In step S5, it is determined whether the input of a large road surface input has been completed or whether the input of a large road surface input has been predicted. The prediction of the input of the large road surface input includes not only the case where the prediction is made at the current time point but also the case where the prediction is made in the future, as in step S2. The determination method in step S5 will be described later. As a result of step S5, when the input of a large road surface input is completed or the input of a large road surface input is not predicted (step S5-Y), the process proceeds to step S7.

  In step S7, a command for returning to the normal shift method is issued. That is, as usual, a command to return to the gear position determined according to the engine load, vehicle speed, etc. in that state is issued. Thereafter, after the flag F is set to 0 (step S8), the flag F is reset.

  On the other hand, as a result of step S5, when the input of a large road surface input is not completed or the input of a large road surface input is not predicted (successfully predicted) (step S5-N), the flag F Is set to 1 (step S6) and then reset. In step S1 after the reset, since the flag F is 1, the process proceeds to step S5. In step S5, input of a large road surface input is completed, or until input of a large road surface input is not predicted, steps S1 and S5 are performed. Is repeated. In other words, the shift stage remains in the OWC non-operating stage (shifting to the OWC operating stage is prohibited) until the input of the large road surface input ends or the input of the large road surface input is not predicted.

  Next, the determination method performed in step S2 will be described. In step S2, it is roughly determined whether (1) there is slipping of the tire and (2) whether the road surface is bad such as a large unevenness on the road surface.

First, (1) a method for determining tire slip will be described.
When driving over a step, the driving wheel slips away from the road surface or when driving on a low mu road. By judging the occurrence of the slip, when the vehicle descends from the step, or when moving from the low mu road to the high mu road, the tire grips (slips), and the road surface becomes large. It is predicted that road surface input will be input.

  With regard to tire slip, it can be determined that tire slip has occurred when it is detected that the difference in rotational speed between the driving wheel and the driven wheel of the vehicle is greater than or equal to a predetermined value. Instead of the rotational speed of the driving wheel, the rotational speed of the rotating member having a fixed relationship with the rotational speed of the driving wheel may be used. Similarly, instead of the rotational speed of the driven wheel, the rotational speed of the rotating member having a fixed relationship with the rotational speed of the driven wheel may be used. Here, the points described below are the same in that a rotating member related to the driving wheel can be used instead and a rotating member related to the driven wheel can be used instead of the driven wheel.

In order to detect the rotational speed difference between the driving wheel and the driven wheel of the vehicle, two rotational speed sensors for detecting the rotational speeds of the driving wheel and the driven wheel are required. On the other hand, there is a rotational speed sensor that detects the rotational speed of the drive wheel, but when there is no rotational speed sensor that detects the rotational speed of the driven wheel, the detected rotational speed of the driven wheel is 2 Two different annealing processes are performed, and the difference between the two signals obtained as a result can be treated as a difference in rotational speed between the driving wheel and the driven wheel. Here, the annealing process is, for example, a process using a low-pass filter for removing vibration components.

  Further, it is possible to predict the occurrence of tire slip on the basis of the road position information and the vehicle position information on which the tire is preferentially recorded on the recording medium (DVD, HD, etc.) of the car navigation system. In addition, road position information on which tires are slippery is recorded on the vehicle recording medium based on the past driving results when the vehicle has traveled in the past, and tire slip occurs based on the information and vehicle position information. Can be predicted. Further, it is possible to predict tire slip based on road position information on which tires are slippery and vehicle position information obtained through communication with other vehicles and communication centers. Such communications include road traffic information communication systems (VICS) and so-called telematics.

Next, (2) a bad road determination method will be described.
When traveling on a rough road with unevenness on the road surface, a large road surface input is actually input, and there is a high possibility that a road input larger than that will be input.

  Whether or not the road is a rough road can be determined by performing a bandpass filter process on the detected rotational speed of the drive wheel. The rotational speed of the drive wheel not only changes depending on the road surface condition such as unevenness, but also changes due to the change in the vehicle speed, and the rotational speed due to the change in the vehicle speed with respect to the detected rotational speed of the drive wheel. By performing a band-pass filter process for removing the change component, it is possible to detect a road surface state such as unevenness.

  Further, as in (1) above, based on the information on the road position of the bad road and the vehicle position information recorded in advance on the recording medium (DVD, HD, etc.) of the car navigation system, the driving on the bad road is predicted. be able to. Further, information on the road position of the bad road is recorded on the recording medium of the vehicle based on the driving performance when the vehicle has traveled in the past, and the driving on the bad road is predicted based on the information and the position information of the vehicle. be able to. Moreover, it is possible to predict a rough road based on the information on the road position of the bad road and the position information of the vehicle obtained through communication with other vehicles and the communication center. Such communications include road traffic information communication systems (VICS) and so-called telematics.

Next, the determination method in step S5 will be described.
First, a method for determining that the large road surface input due to the tire slip (1) is ended or that the large road surface input due to the tire slip is not predicted will be described.

  When the rotational speed of the driving wheel suddenly decreases, it can be determined that the end of the large road surface input or the large road surface input is no longer predicted. The sudden decrease in the rotational speed of the drive wheels means that the drive wheels touched and gripped the road surface, and a large road surface input was entered along with the grip. It is judged that large road surface input due to slipping is no longer predicted.

Even if there is no sudden decrease in the rotational speed of the drive wheels, it is determined in step S2 that a large road surface input is no longer predicted after a predetermined time has elapsed since it was predicted that there was a large road surface input. Can do. When there is no large road surface input for a sufficiently long time from the prediction time point, it can be determined that the situation changes from the time point when the tire slip is predicted, and there is no possibility that a large road surface input is input. Furthermore, it can be determined that there is no fear of a large road surface input due to tire slip based on the navigation information and the information obtained by the communication and the vehicle position information.

  Next, a method for determining that the large road surface input due to the rough road in (2) has been completed or that the large road surface input due to the bad road is not predicted will be described. If it is determined that the vehicle is not traveling on a rough road by using the result of the bandpass filter processing described in (2) above, the fact that the large road surface input by the bad road in (2) has been completed or is bad. It can be determined that a large road surface input by the road is no longer predicted. Further, it can be determined that there is no fear of a large road surface input due to a bad road based on the navigation information and the information obtained by the communication and the position information of the vehicle.

  In step S2 of FIG. 1, if there is at least one of the tire slip of (1) and the bad road of (2) (if predicted), it is predicted that there is a large road surface input (step S2). -Y). On the other hand, in step S5, when neither the tire slip of (1) and the bad road of (2) are present (when it is not predicted), it is determined that the large road surface input is not completed or predicted ( Step S5-Y).

  Next, an example of the determination method performed in step S2 of FIG. 1 will be described in detail with reference to FIG. FIG. 2 is an example of a method for determining whether or not the road surface on which the vehicle is traveling is a bad road.

  First, the output rotation speed No (i) that is the rotation speed of the output shaft 6 of the automatic transmission 10 is read, and the change rate ΔNo (i) is calculated (step S301). This output rotational speed No (i) corresponds to the rotational speed of the driving wheel or the rotational speed of the rotating member having a fixed relationship therewith. Further, the change rate ΔNo (i) corresponds to the rotational acceleration of the driving wheel or the rotating member having a fixed relationship therewith.

  The rotational acceleration ΔNo (i) obtained in this way includes changes in vehicle speed, disturbances, and the like. Therefore, a vibration component ΔNo_vib (i) based on the road surface unevenness state is calculated by performing, for example, a bandpass filter process on the rotational acceleration ΔNo (i) in a predetermined frequency band (step S302).

  It is determined whether or not N filter processing values ΔNo_vib (i) obtained in this way can be accumulated (step S303). That is, it is determined whether or not N band pass filter processed values ΔNo_vib (i) have been obtained before the current time point. If the result of step S303 is negative, the process returns and waits for N bandpass filter processing values ΔNo_vib (i) to be obtained.

  If the determination in step S303 is affirmative, N absolute values (time window integration) of the absolute values of the bandpass filter processing value ΔNo_vib (i) already obtained at the current time point are accumulated (step S304). Further, a low-pass filter processing value Sno_lo (i) obtained by processing the accumulated value (integrated value) Sno (i) with a low-pass filter is calculated (step S305).

  Next, it is determined whether or not the low-pass filter processing value Sno_lo (i) is larger than a predetermined reference value Sno_akr (step S306). If an affirmative determination is made in step S306, it is determined that the vehicle is traveling on a non-good road (bad road) having unevenness larger than a certain level on the road surface (step S307). In this case, it is determined that a large road surface input is predicted (step S308). In this case, a positive determination is made in step S2 of FIG.

On the other hand, when a negative determination is made in step S306 in FIG. 2, it is determined that the road surface has no unevenness or is traveling on a good road (flat road) with less unevenness (step S309). . In this case, it is not predicted that a large road surface input will be input (step S310). In this case, a negative determination is made in step S2 of FIG.

  When predicting the presence or absence of a large road surface input, when the method of FIG. 2 is used, the rotational acceleration of a wheel or a rotating member having a fixed relationship with the wheel is obtained, and the unevenness of the road surface is determined based on the filtered value. Since the state is determined, if there is a change such as unevenness on the road surface, this immediately appears as a large rotational acceleration, so the uneven state of the road surface can be detected quickly. More specifically, if the rotational speed is changed by, for example, a sine curve, the rotational acceleration is represented by a cosine curve, and the phase is advanced by a quarter cycle. Therefore, even if the determination is made by comparing the threshold values, the timing of exceeding the threshold value is advanced, so that it is possible to quickly detect the uneven state of the road surface.

  Further, according to the method of FIG. 2, an integrated value of the filter value (preferably its absolute value) is obtained, and when the filter value of the integrated value (low-pass filter processing value) is larger than a predetermined value, the road surface unevenness state is determined. Since the determination is made, it is possible to accurately determine the uneven state of the road surface by eliminating the disturbance factor.

  Next, an example of another determination method in step S2 of FIG. 1 will be described in detail with reference to FIG. FIG. 3 is an example of a method for determining whether or not the road surface on which the vehicle is traveling is a bad road and the presence or absence of tire slip.

  First, the output rotation speed No, which is the rotation speed of the output shaft 6 of the automatic transmission 10, is read (step S401). This output rotational speed No is the rotational speed of the driving wheel or the rotational speed of the rotating member having a fixed relationship therewith. This rotational speed changes with changes in the vehicle speed, and also changes according to road surface conditions such as unevenness, and further includes components such as noise, so for example as shown in FIG. Such a signal.

  Next, bandpass filter processing is performed for the output rotation speed No (step S402). This is, for example, a process for removing a change component of the rotational speed due to a change in the vehicle speed, and a signal obtained as a result is as shown in FIG. 4B, for example. The absolute value ((C) of FIG. 4) of the signal processed in this way is taken (step S403). Using the data of FIG. 4C as one data, n pieces of data going back from the present time are integrated (step S404). The integration in step S404 is time window integration over a time corresponding to n pieces of data. On the other hand, the change amount of the output rotational speed No or the rotational acceleration ΔNo is calculated (step S405).

  Next, it is determined whether or not there is a tire slip or road surface unevenness (step S406). That is, it is determined whether the rate of change (acceleration) ΔNo of the output rotational speed No is equal to or greater than the first threshold value ΔNo1. When the drive wheel slips on a low mu road or descends from the uneven surface of the road surface, the rotational speed of the driving wheel and the rotational speed of the rotating member having a fixed relationship with the driving wheel increase rapidly. It appears as an increase in the acceleration ΔNo of the output rotational speed No. Therefore, when a positive determination is made in step S406, it is predicted that there is a large road surface input (step S407). In this case, a positive determination is made in step S2 of FIG.

On the other hand, if a negative determination is made in step S406, it is determined whether or not the integrated value (rotational speed time window integrated value) integrated in step S404 has exceeded a predetermined value ( Step S408). This integrated value is obtained by subjecting the detected value of the rotational speed of the drive wheel or a member rotating in a fixed relationship to the band-pass filter processing and integrating the time window, and thus includes a slight rotational fluctuation. ing. In other words, the value reflects a slight unevenness of the road surface. The value increases or decreases for each time window, and eventually reflects the state of the road surface traveled between the present time and a predetermined time before.

  Therefore, if the integrated value exceeds the predetermined value and an affirmative determination is made in step S408, the rotational fluctuation based on the road surface condition is large to some extent and continues. As a result, it is predicted that there is a large road surface input (step S407).

  On the other hand, when a negative determination is made in step S408, it is determined that the road surface has no unevenness or a so-called good road with little unevenness, and it is not predicted that there is a large road surface input (step S409). In this case, a negative determination is made in step S2 of FIG.

  According to the method shown in FIG. 3, the detection signal based on the rotational acceleration of any rotating member on the output side of the automatic transmission 10 is not limited to the bandpass filter processing, but the processing values are integrated and the integrated value is obtained. Since the road surface state is determined based on the road surface, an accurate road surface state can be detected, which is useful for accurately predicting the presence or absence of a large road surface input.

  Next, an example of another determination method in step S2 of FIG. 1 will be described in detail with reference to FIG. The method of FIG. 5 improves the accuracy of determining the road surface condition by removing the vibration component that becomes noise.

  First, similarly to the method of FIG. 3, reading of the output rotation speed No (step S501) and its band pass filter processing (step S502) are performed. Next, it is determined whether or not the bandpass filter processing values can be accumulated (integrated) (step S503). If a negative determination is made in step S503 due to the failure to integrate, the process returns. On the other hand, if a positive determination is made in step S503, the absolute value of the bandpass filter processing value is taken and the n pieces of data are integrated (step S504). That is, time window integration is performed.

  An annealing process is performed to remove the vibration component of the integrated value (step S505). This is low-pass filter processing as an example. Next, it is determined whether or not the integrated value Sno_lo (i) after the low-pass filter process is larger than a predetermined reference value Sno1 (step S506).

  This step S506 is a determination step according to step S406 shown in FIG. Therefore, when an affirmative determination is made in step S506, it means that the vehicle is traveling on a non-good road (bad road), and it is predicted that the road surface input is large (step S507). In this case, a positive determination is made in step S2 of FIG.

  On the other hand, if a negative determination is made in step S506, the vehicle is traveling on a good road, and therefore it is not predicted that a large road surface input will be input (step S508). The reference value Sno1 may be a constant value, but may be a value that changes according to the traveling state of the vehicle, such as acceleration, accelerator opening, and vehicle speed.

  According to the method of FIG. 5, the integrated value of the output rotation speed No subjected to the band pass filter processing is further smoothed (for example, low pass filter processing), and the road surface state is determined based on the obtained value. The road surface condition can be accurately determined.

(Second Embodiment)
Next, a second embodiment of the control device for an automatic transmission according to the present invention will be described with reference to FIG. In the sixth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 6, steps S1 to S5 have the same contents as steps S1 to S5 in FIG. In step S5, it is determined that a large road surface input has been completed or a large road surface input is no longer predicted (S5-Y). In step S7, when returning to the normal stage, the operation to return to the normal stage is a downshift. In some cases (S9-Y), for safety and prevention of driver discomfort, the vehicle is returned under conditions (S10) that do not cause power-on down or sudden engine braking. When returning to the normal speed in step S7, unlike the case of shifting to the OWC non-operating speed in step S4 so as not to affect the durability of the one-way clutch, a special and quick shifting operation is required. I don't mean.

  In order to prevent the power-on-down from occurring when the OWC inactive stage is downshifted and returned to the normal stage, for example, the accelerator is returned in a fully closed state. This is because the greater the accelerator opening, the greater the torque step during downshifting. In addition, when downshifting to a gear stage where the engine brake is effective, in order to prevent sudden engine braking, the vehicle speed is restored in a low speed range (region where the engine speed is low) or the clutch is engaged. Return with the pressure reduced. Hereinafter, an example of the specific method will be described.

  As shown in FIG. 6, step S9 and step S10 are added between step S5 and step S7. In step S9, it is determined whether or not the normal speed corresponding to the engine load, vehicle speed, etc. at that time is downshifted from the OWC non-operating speed shifted and maintained in step S4. If not downshifting (step S9-N), the normal stage is restored as it is (step S7). This is because there is no need to worry about sudden engine braking unless it is a downshift. When downshifting is performed (step S9-Y), the process proceeds to step S10.

  In step S10, it is determined whether or not the engine load (or throttle opening) is not more than a predetermined value and the vehicle speed is not more than a predetermined value. If a positive determination is made in step S10, the process returns to the normal stage as it is (step S7). If a negative determination is made in step S10, the process is returned and step S9 is executed again. If a negative determination is made in step S9 or a positive determination is made in step S10, the process returns to the normal stage ( Step S7).

  In the present example, in the case of downshifting, the configuration does not return to the normal stage unless the determination in step S10 is positive, but the present invention is not limited to this method. For example, if at least one of the conditions that the engine load is equal to or lower than a predetermined value and the vehicle speed is equal to or lower than the predetermined value is satisfied, the normal stage can be allowed to return.

  In each of the above embodiments, the “set value” of the torque applied to the one-way clutch, which is a reference for setting the OWC operation stage and the non-OWC operation stage, does not necessarily have to be common to all the one-way clutches. It can be set for each one-way clutch in consideration of the strength and frequency of use of each one-way clutch.

It is a flowchart which shows the control method of 1st Embodiment of the control apparatus of the automatic transmission of this invention. It is a flowchart which shows an example of the rough road determination method performed in the control method of 1st Embodiment of the control apparatus of the automatic transmission of this invention. It is a flowchart which shows the other example of the rough road determination method performed in the control method of 1st Embodiment of the control apparatus of the automatic transmission of this invention. It is explanatory drawing explaining the content of the step of the rough road determination method of FIG. It is a flowchart which shows an example of the determination method of the road surface state performed in the control method of 1st Embodiment of the control apparatus of the automatic transmission of this invention. It is a flowchart which shows the control method of 2nd Embodiment of the control apparatus of the automatic transmission of this invention. It is explanatory drawing which shows the automatic transmission used in 1st Embodiment of the control apparatus of the automatic transmission of this invention. It is a figure which shows the action | operation table | surface of the automatic transmission used by 1st Embodiment of the control apparatus of the automatic transmission of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gear transmission mechanism 10 Automatic transmission F0 O / D one-way clutch F1 1st one-way clutch F2 2nd one-way clutch

Claims (5)

A control device for an automatic transmission, wherein a part of a plurality of shiftable shift stages is configured by operating a one-way clutch,
Estimating means for estimating that a load of a predetermined value or more is input to the automatic transmission from the road surface;
Some of the plurality of shift speeds are configured by operating a one-way clutch, and when a load greater than a predetermined value is input to the automatic transmission from the road surface, the one-way clutch exceeds a set value. A shift that is registered as a one-way clutch operating stage as a shift stage that may be loaded, and that some of the plurality of shift stages are configured without the one-way clutch operating. Or a one-way clutch is operated, and there is no possibility that a load greater than a set value is applied to the one-way clutch when a load greater than a predetermined value is input to the automatic transmission from the road surface. A registration unit that is registered as a one-way clutch inoperative stage,
When it is estimated that a load of a predetermined value or more is input to the automatic transmission from the road surface, if the shift stage of the automatic transmission is the one-way clutch operating stage, the shift stage of the automatic transmission is changed. And a control unit that controls the one-way clutch to be in an inoperative stage. The control device for an automatic transmission according to claim 1,
The control unit is configured to operate the one-way clutch when the shift stage of the automatic transmission is the one-way clutch operation stage when it is estimated that a load greater than a predetermined value is not input to the automatic transmission from the road surface. A control device for an automatic transmission, characterized by traveling in stages . The control apparatus for an automatic transmission according to claim 1 or 2,
The automatic transmission control apparatus characterized in that the estimation means determines tire slip and estimates that a load greater than or equal to a predetermined value is input based on the determination result. The control device for an automatic transmission according to any one of claims 1 to 3 ,
The estimation unit determines a road surface state, and estimates that a load greater than a predetermined value is input based on the determination result. The control apparatus for an automatic transmission according to any one of claims 1 to 4,
  The estimation means estimates that a load greater than or equal to a predetermined value is input based on information indicating a road surface state stored in advance in the vehicle or information indicating a road surface state input through communication with the outside of the vehicle.
  A control device for an automatic transmission.

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